Pyrophoric alloys



United States Patent M PYROPHORIC ALLOYS Otto Smetana, Hans Nowotny, and Kurt Komarek, Vienna, Austria No Drawing. Application February 12, 1954, Serial No. 410,028

Claims priority, application Austria February 26, 1953 1 Claim. (Cl. 75-134) There are metals and alloys which exhibit pyrophoric eifects in response to impact and friction, giving sparks when being struck, rubbed, filed and the like. In technically useful alloys these mechanically separated sparks must be hot enough and their combustion temperature must prevail long enough to ignite suitable substances such as combustible gases and liquid or solid fuels. The pyrophoric effect must be producible readily and at any time, whereas the consumption of pyrophoric metal for the formation of sparks should be small. The pyrophoric metal must resist for sufiiciently long periods the corrosive influences to which it is subjected in normal use.

We have now found new, highly pyrophoric alloys, which are suitable for use in lighters and other applications. These alloys, which form the subject of the present invention, are alloys of titanium with tin or lead or with both, antimony being present up to a maximum of 25%, if desired. Titanium-lead alloys containing substantially more than 52% Pb are inhomogenous; they show segregation. Titanium-lead alloys containing less than 40% lead are too hard for industrial purposes. The lead may be replaced in part or entirely by tin, but those alloys are inferior in ignition quality to titanium-lead alloys.

The alloys may be produced in any desired way. The following example illustrates such procedure of production: 540 grams titanium powder containing 99% titanium are mixed with 240 grams lead powder (99.9% pure) and 700 grams coarse antimony powder and without addition of a binder are pressed in a hydraulic press to form buttons 30 mm. in diameter and 30 mm. high.

2,815,281 Patented Dec. 3, 1957 500 grams of said buttons in a cylindrical crucible of dense graphite having the dimensions: 48 mm. internal diameter, mm. external diameter, length 300 mm., are inserted into a tiltable, entirely closed carbon-tube short-circuit furnace. The furnace space is evacuated down to 0.05 mm. Hg, pure argon is admitted to a pressure of 700 mm. Hg, and the electric power is connected. The current is initially 200 amp. and during 10 minutes is gradually increased to the final value of 500 amp. The final voltage is 27 volts. After 12 minutes the mass has been melted. The pressure in the furnace rises to 1400 mm. Hg. Melting the remainder of the buttons, which are gradually added to the melt by a suitable device, takes 25 additional minutes. After the melting has been completed the furnace is tilted whereafter the metal flows into the chill mould preheated to 500 deg. C.

Example Percent byweight Ti Sn Zr Ce Fe Al References Cited in the file of this patent UNITED STATES PATENTS Hoffman Oct. 24, 1911 Anicetti Dec. 6, 1949 OTHER REFERENCES Explosive Characteristics of Titanium, Zirconium, Thorium, Uranium and Their Hydrides, Bureau of Mines Report of Investigations 4835, U. S. Dept. of Interior, December 1951, pages 1, 2 and 16. 

